Wire-range radio-frequency tuner



Feb. 14, 1956 I, R. VERSOY, JR

WIDE-RANGE RADIO-FREQUENCY TUNER Filed Aug. 25, 1952 J %)IVNVENTORI Mfiw ATTORNEYS.

WISE-RANGE RADIO-FREQUENCY TUNER Irving R. Verso Jr., Norwalk, Cnn.,assignor to Aladdin Industries, Incorporated, Chicago, 111., a'CDIPOIQUOROQ Illinois Application August 25,1952, Serial No. 396,157

6 Claims. .(Cl. 333-24) This invention relates to tuners for V. H. F.and U. H. F. circuits, particularly to tuners adapted for use inapplications requiring a Wide range of frequency variation.

Specifically, the present invention relates to wide-range tuners of thetype embodying a pair of energy-transfer elements and an inductor havingnon-uniform inductance per unit length, the inductor being movablerelatively to both the energy-transfer elements.

in one advantageous form of such tuners, the energytransfer elements arefixed in position with respect to one another, the inductor beingaxially movable through or alongside the transfer elements. The exchangeof energy between the inductor and the energy-transfer elements ispreferably accomplished by capacitive transfer.

A tuner of this type makes possible continuous tuning over heretoforeunheard-of frequency ranges, such as 25 to 1. From the mechanicalstandpoint, however, such a Wide frequency range usually has required arather extensive range of axial movement by the inductor. It is theobject of the present invention to provide a widerange tuner of theforegoing character which has the advantage of requiring substantiallyless axial inductor movement to cover a given frequency range or seriesof frequency ranges. Another object of the present invention is toprovide a tandem inductor arrangement which facilitates use of theaforesaid type of tuner in applications wherein a plurality of frequencybands are to be covered, rather than a continuous frequency range.

in the appended drawing, Ihave disclosed an illustrative embodiment ofmy invention; Fig. 1 is a perspective view showing the externalappearance of a typical embodiment of my tuner; Fig. 2 is a sectionalview, in the vertical plane, of the Fig. l apparatus; and Fig. 3 is asectional view taken in a plane perpendicular to that of Fig. 2, alongthe line 33 of Fig. 2.

In Fig. l l have shown my tuner mounted on a suitable block 11 oflow-loss insulating material such as polystyrene. Suitably secured toblock 11, as by screws 12, l have provided a pair of energy-transferelements 13 and 1 2-, preferably formed by suitable machining fromrelatively massive blocks of metal such as brass, copper, or aluminum.The blocks 13 and 14 are mounted upright on base 11 and may haveinterposed between them a'guide block 15 of insulating material such aspolystyrene.

As may be readily seen from Fig. 2, all the elements 13, 1d, and 155 areprovided with a plurality of parallel bores marked respectively 16, 17,and 18. The bores in the respective elements 13, 14, and 15 are arrangedfor registration, so as to provide a plurality of parallel passagesextending entirely throughout the assembly.

As will be explained in a subsequent paragraph, inductors are adapted toslide within the bores 16, 17, and 18, and the function of theinsulating block 15 is to insure that all the inductors are effectivelyguided within the bores, regardless of their axial position. In otherwords, the block 15 has nothing to do with the electrical performance ofthe invention and can .be omitted if other suitable measures are takento prevent the inductors from 'nited States Patent 0 2,735,072 PatentedFeb. 14, 1956 2. binding or jamming within the bores drilled in themetal blocks 13 and 14.

Contact lugs 19 may be provided as desired on the blocks 13 and 14, tofacilitate the connection of an external circuit to the tuner.

As indicated heretofore, the energy exchange to and from the inductorsis preferably accomplished by capacitive rather than conductive energytransfer. To facilitate that, I have provided within each of the bores16, 17, and 13, in all the portion of those bores within the metalblocks 13 and 14, thin plastic inner sleeves 21. Sleeves 21 provide athin insulating layer on the inner surfaces of bores 16, 17, and 18, andat the same time provide a smooth low-friction surface for the inductorsto slide on.

The inductors mentioned are suitably wound on a plurality of rods orforms made of suitable low-loss material. The rods are mounted inparallel relation, with spacing adapted to permit them to slidesimultaneously within the bores 16, 17, and 18. The rods are identifiedby reference numerals 26, 27, and 28 respectively. As illustrative of asuitable mechanical arrangement for simultaneously sliding the rods 26,27, and 28, l have shown a yoke 29 rigidly receiving all the rods.

The highest-frequency inductor should normally be placed nearest theexternal connections to the associated tube, since the total circuitinductance is thereby reduced.

It is to be understood that my choice of three inductors and three-boreenergy-transfer elements was arbitrary and for illustration only. Anydesired number maybe used.

The inductor 36, wound on rod 26, is formed of wire wound on rod 26 in amanner such that its inductance per unit length is non-uniform.Specifically, inductor 36 is provided with a number of closely woundturns at the left end thereof, as viewed in Fig. 2, and the remainingturns are spaced with ever-increasing spacing.

Inductor 37, wound on rod 27, is placed in staggered position relativeto inductor 36, commencing a substantial distance to the right thereof,as viewed in Fig. 2. The length of coil 37 is substantially the same asthe length of coil 36, but its inductance is far less. In theillustration shown, inductor 37 is wound of ribbon having substantiallyequal winding pitch throughout but gradually increasing in ribbon widthfrom the left to the right ends of the coil. As a result, the inductanceper unit length of inductor 37 is also non-uniform.

Inductor 38 is made in a manner similar to inductor 37, except that itis staggered still further to the right and is made of ribbon havinggreater width and greater pitch, resulting in substantially lessinductance. It shares, however, the characteristic of the otherinductors in that its inductance per unit length is variable.

The inductors 36, 37, and 38 are all of substantially the same length,but they vary greatly one from another in total inductance. Theinductors are staggered according to the pattern which provides thatonly one of the inductors can at any one time bridge the insulated zonebetween the energy-transfer elements 13 and 14. In the position of therods 26, 27, and 28 shown in Fig. 2, inductor 35 is barely bridging thespace between the elements 13 and 14, and, upon being moved slightlyfurther to the left, inductor 36 will be closely coupled capacitively toboth energy-transfer elements 13 and 14-. As further leftward movementof the inductors continues, the total inductance effectively bridgedbetween the elements 13 and 14 will become greatly reduced, since theclosely wound portion of inductor 36 will be involved withinenergy-transfer element 13. This will result in reducing substantiallyto zero the effective inductance of the closely wound portion of thecoil, leaving as the inductance effectively in the circuit that which ispossessed by the portion of the coil remaining between the elements 13and 14.

With still further leftward movement of the inductors,

the right end of inductor 36 will pass completely beyond energy-transferelement 14, leaving inductor 36 substantially disconnected from thecircuit. Almost immediately thereafter, as the rods continue to move tothe left, the left end of inductor 37 will pass into intimate capacitiverelation with element 13 and inductor 37 will thereby be effectivelyplaced in the external circuit connected to lugs 19. Further leftwardmovement of the yoke 2 will cause the effective inductance in thecircuit to be reduced still further, because of the non-uniforminductance characteristics of the coil 37.

Finally, as coil 37 moves so far leftward as to clear elementl4,inductor 38 will come into the circuit in the manner already explained.

It will be understood that any desired mechanical arrangement may beprovided for the systematic axial movement of rods 26, 27, and 28.

The outstanding advantage of the present invention over the type ofprior structure heretofore discussed is that my present inventionpermits of wide-range tuning over a plurality of bands with a verysubstantially reduced linear movement of the inductors. Furthermore, itpermits more gradual change of inductance with length, for any givenavailable range of movement, and thereby provides greater bandspread andcorrespondingly greater ease of tuning.

While I have in this specification described in con siderable detail aparticular embodiment of my invention, it is to be understood that theexample shown is purely illustrative and that many changes can be madein the apparatus shown without departing from the spirit of myinvention. For example, the energy-transfer elements 13 and 14 can be ofany desired conformation or length. in the drawing, 1 have illustratedthe fact that one or both of the contact elements may, if desired, beelongated so as to envelop substantially all of the inductors notactually bridging the contact elements. Further, while I have hereinshown the inductors wound on cylindrical forms, and have shown thecooperating bores in the energytransfer elements similarly cylindricalin shape, it will be readily seen that the invention could be practicedby the use of arcuate coil forms and arcuate bores.

Also, while I have shown insulating sleeves 21 as a means of insuringcapacitive energy interchange between the elements 13 and 14, on the onehand, and the inductors, on the other hand, the same result could beaccomplished by providing the inductors with a thin insulating layer.

A related invention is disclosed and claimed in the co-pendingapplication of Harold T. Lyman, Serial No. 305,629, filed August 21,1952.

Such points are a matter of choice and design, and I desire them to beembraced within the scope of my invention as defined in the appendedclaims.

I claim:

1. A wide-range radio-frequency tuner, comprising a pair of conductiveenergy-exchange electrode elements fixedly spaced apart relative to oneanother, each of said elements being provided with a plurality ofparallel transversely spaced, generally cylindrical channels therein,said channels in each of said elements being axially aligned with thecorresponding channels in the other of said elements, a plurality ofgenerally helical inductance coils axially aligned with said respectivechannels and mounted for longitudinal movement therein, means providinga thin layer of insulating material interposed between said coils andeach of said channels to limit energy exchange therebetween primarily tocapacitive energy interchange, each of said coilshaving non-uniforminductance per unit length along the length thereof, each of said coilsbeing longer than the spacing between said electrode elements and beingmovable into and along a range of positions with said coil bridging thespace between said elements and intimately coupled thereto inenergy-exchange relation therewith, said coils being longitudinallystaggered in position and rigidly mounted with respect to one anotherand thereby being movable successively into bridging relation betweensaid electrode elements, with only one of said coils in bridgingrelation between said elements for any one position of said coils insaid channels.

2. A wide-range radio-frequency tuner, comprising a pair of conductiveenergy-exchange electrode elements fixedly spaced apart relative to oneanother, each of said elements being provided with a plurality ofparallel transversely spaced, generally cylindrical channels therein,said channels in each of said elements being axially aligned with thecorresponding channels in the other of said elements, a plurality ofgenerally helical inductance coils axially aligned with said respectivechannels and mounted for longitudinal movement therein, each of saidcoils having non-uniform inductance per unit length along the lengththereof, each of said coils being longer than the spacing between saidelectrode elements and being movable into and along a range of positionswith said coil bridging the space between said elements and intimatelycoupled thereto in energy-exchange relation therewith, said coils beinglongitudinally staggered and fixed in position with respect to oneanother and thereby being movable successively into bridging relationbetween said electrode elements.

3. A wide-range radio-frequency tuner, comprising a pair of conductiveenergy-exchange electrode elements fixedly spaced apart relative to oneanother, each of said elements being provided with a plurality ofparallel transversely spaced channels therein, said channels in each ofsaid elements being axially aligned with the corresponding channels inthe other of said elements, a plurality of generally helical inductancecoils axially aligned with said respective channels and mounted forlongitudinal movement therein, means providing a thin layer ofinsulating material interposed between said coils and each of saidchannels to limit energy exchange therebetween primarily to capacitiveenergy interchange, each of said coils having non-uniform inductance perunit length along the length thereof, each of said coils being longerthan the spacing between said electrode elements and being movable intoand along a range of positions with said coil bridging the space betweensaid elements and intimately coupled thereto in energy-exchange relationtherewith, said coils being longitudinally staggered and fixed inposition with respect to one another and thereby being movablesuccessively into bridging relation between said electrode elements.

4. A wide-range radio-frequency tuner, comprising a pair of conductiveenergy-exchange electrode elements fixedly spaced apart relative to oneanother, each of said elements being provided with a plurality ofparallel transversely spaced channels therein, said channels in each ofsaid elements being axially aligned with the corresponding channels inthe other of said elements, a plurality of generally helical inductancecoils axially aligned with said respective channels and mounted forlongitudinal move ment therein, each of said coils having non-uniforminductance per unit length-along the length thereof, each of said coilsbeing longer than the spacing between said electrode elements and beingmovable into and along a range of positions with said coil bridging thespace between said elements and intimately coupled thereto inenergy-exchange relation therewith, said coils being longitudinallystaggered and fixed in position with respect to one another and therebybeing movable successively into bridging relation between said electrodeelements.

5. A wide-range radio-frequency tuner, comprising a pair of conductiveenergy-exchange electrode elements fixedly spaced apart relative to oneanother, each of said elements being provided with a plurality ofparallel transversely spaced, generally cylindrical channels therein,said channels in each of said elements being axially aligned with thecorresponding channels in the other of said elements, a plurality ofgenerally helical inductance coils axially aligned with said respectivechannels and mounted for longitudinal movement therein, means providinga thin layer of insulating material interposed between said coils andeach 01' said channels to limit energy exchange therebetween primarilyto capacitive energy interchange, each of said coils having non-uniforminductance per unit length along the length thereof, each of said coilsbeing longer than the spacing between said electrode elements and beingmovable into and through a range of positions with said coil bridgingthe space between said elements and intimately coupled thereto inenergy-exchange relation therewith, and means for moving said coilssuccessively into and through said range of positions with said coilssuccessively in bridging relation between said electrode elements.

6. A wide-range radio-frequency tuner, comprising a pair of conductiveenergy-exchange electrode elements fixedly spaced apart relative to oneanother, each of said elements being provided with a plurality ofparallel transversely spaced channels therein, said channels in each ofsaid elements being axially aligned with the corresponding channels inthe other of said elements, a plurality of generally helical inductancecoils axially aligned with said respective channels and mounted forlongitudinal movement therein, each of said coils having non-uniforminductance per unit length along the length thereof, each of said coilsbeing longer than the spacing between said electrode elements and beingmovable into and through a range of positions with said coil bridgingthe space between said elements and intimately coupled thereto inenergy-exchange relation therewith, and means for moving said coilssuccessively into and through said range of positions with said coilssuccessively in bridging relation between said electrode elements.

References Cited in the file of this patent UNITED STATES PATENTS Re.19,232 Dalpayrat July 10, 1934 1,258,423 Lowenstein Mar. 5, 19182,250,366 Frisbee July 22, 1941 2,589,092 Kihn et a1. Mar. 11, 19522,622,203 Kiebert, In, et al Dec. 16, 1952 FOREIGN PATENTS 425,329 GreatBritain Mar. 12, 1935

